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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 02/10] KVM: Drop bogus "pfn != 0" guard from kvm_release_pfn()
Date: Fri, 29 Apr 2022 01:04:08 +0000	[thread overview]
Message-ID: <20220429010416.2788472-3-seanjc@google.com> (raw)
In-Reply-To: <20220429010416.2788472-1-seanjc@google.com>

Remove a check from kvm_release_pfn() to bail if the provided @pfn is
zero.  Zero is a perfectly valid pfn on most architectures, and should
not be used to indicate an error or an invalid pfn.  The bogus check was
added by commit 917248144db5 ("x86/kvm: Cache gfn to pfn translation"),
which also did the bad thing of zeroing the pfn and gfn to mark a cache
invalid.  Thankfully, that bad behavior was axed by commit 357a18ad230f
("KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache").

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 virt/kvm/kvm_main.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 04ed4334473c..154c3dda7010 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2723,9 +2723,6 @@ EXPORT_SYMBOL_GPL(gfn_to_page);
 
 void kvm_release_pfn(kvm_pfn_t pfn, bool dirty)
 {
-	if (pfn == 0)
-		return;
-
 	if (dirty)
 		kvm_release_pfn_dirty(pfn);
 	else
-- 
2.36.0.464.gb9c8b46e94-goog


  parent reply	other threads:[~2022-04-29  1:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-29  1:04 [PATCH 00/10] KVM: Clean up 'struct page' / pfn helpers Sean Christopherson
2022-04-29  1:04 ` [PATCH 01/10] KVM: Do not zero initialize 'pfn' in hva_to_pfn() Sean Christopherson
2022-06-16 14:54   ` Paolo Bonzini
2022-06-16 16:51     ` Sean Christopherson
2022-04-29  1:04 ` Sean Christopherson [this message]
2022-04-29  1:04 ` [PATCH 03/10] KVM: Don't set Accessed/Dirty bits for ZERO_PAGE Sean Christopherson
2022-04-29  1:04 ` [PATCH 04/10] KVM: Avoid pfn_to_page() and vice versa when releasing pages Sean Christopherson
2022-06-16 15:00   ` Paolo Bonzini
2022-06-16 16:54     ` Sean Christopherson
2022-04-29  1:04 ` [PATCH 05/10] KVM: nVMX: Use kvm_vcpu_map() to get/pin vmcs12's APIC-access page Sean Christopherson
2022-04-29  1:04 ` [PATCH 06/10] KVM: Don't WARN if kvm_pfn_to_page() encounters a "reserved" pfn Sean Christopherson
2022-04-29  1:04 ` [PATCH 07/10] KVM: Remove kvm_vcpu_gfn_to_page() and kvm_vcpu_gpa_to_page() Sean Christopherson
2022-04-29  1:04 ` [PATCH 08/10] KVM: Take a 'struct page', not a pfn in kvm_is_zone_device_page() Sean Christopherson
2022-04-29  1:04 ` [PATCH 09/10] KVM: Rename/refactor kvm_is_reserved_pfn() to kvm_pfn_to_refcounted_page() Sean Christopherson
2022-04-29  1:04 ` [PATCH 10/10] KVM: x86/mmu: Shove refcounted page dependency into host_pfn_mapping_level() Sean Christopherson
2022-06-16 15:21 ` [PATCH 00/10] KVM: Clean up 'struct page' / pfn helpers Paolo Bonzini

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